A new Yale-led study of fungi competition illustrates that maintaining a diverse collection of species indeed not only safeguards weaker species but also protects the genetic diversity of the larger community.

For the study, the researchers observed interactions between 37 distinct types of wood-decay fungi, which are any species of fungi that grow on dead wood. Unlike other plants, fungi species grow toward other species and compete for space.

Typically the fungi would meet near the center of the petri dish after about 20 days, after which they would begin an “interference competition” in which each species sought to overtake the other and claim available space.

Often the competitions would end in a stalemate. But in many cases the stronger species would overtake the other, growing on top of and then decomposing the weaker species.

While the most competitive fungal species tended to grow fast, an effective offensive strategy, the researchers found that other species were more adept at playing defense. Some fungal species, for example, tended to remain fixed in one location, developing a dense biomass that became difficult to overcome even by the best offensive competitors. In so doing, these defensive fungi created a buffer between the stronger species and a weaker species.